Mercurial > vba-linux

     1 /* 7zCrc.c -- CRC32 calculation

     2 2008-08-05

     3 Igor Pavlov

     4 Public domain */

     5 

     6 #include "7zCrc.h"

     7 

     8 #define kCrcPoly 0xEDB88320

     9 UInt32 g_CrcTable[256];

    10 

    11 void MY_FAST_CALL CrcGenerateTable(void)

    12 {

    13   UInt32 i;

    14   for (i = 0; i < 256; i++)

    15   {

    16     UInt32 r = i;

    17     int j;

    18     for (j = 0; j < 8; j++)

    19       r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));

    20     g_CrcTable[i] = r;

    21   }

    22 }

    23 

    24 UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size)

    25 {

    26   const Byte *p = (const Byte *)data;

    27   for (; size > 0 ; size--, p++)

    28     v = CRC_UPDATE_BYTE(v, *p);

    29   return v;

    30 }

    31 

    32 UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size)

    33 {

    34   return CrcUpdate(CRC_INIT_VAL, data, size) ^ 0xFFFFFFFF;

    35 }
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 03 Mar 2012 10:35:58 -0600
parents	f9f4f1b99eed
children